Phase calibration has been widely discussed in SAR (Synthetic Aperture Radar) literature, but not as many solutions have been implemented due to the difficulty in separating the various contributions. The aim of this project is to define a phase calibration method which allows to remove unwanted phase terms from each SLC (Single Look Complex). Particular attention will be paid to SAR system geometry errors, atmospheric contribution to the electromagnetic wave propagation, sensor impairments and the unwanted effects on new SAR acquisition modes to the SLC phase.